Density to Weight Calculator

Multiply density by volume: W = ρ × V. Convert both to consistent units first (for example density in kg/m³ and volume in m³ gives mass in kg). This density to weight calculator does the unit conversion and the multiplication for you — just enter the numbers and pick the units.

The formula is weight (mass) = density × volume. In SI units: mass in kilograms = density in kg/m³ × volume in m³. To get true weight as a force, multiply the result by standard gravity (9.80665 m/s²) to get newtons.

Density × volume technically gives mass (kg, lb), which does not change with location. True weight is a force — mass times local gravity — measured in newtons (N) or pound-force (lbf). The calculator shows both: the mass result and its force equivalent using g = 9.80665 m/s².

Multiply the density in kg/m³ by the volume in cubic meters. Example: a block with density 2400 kg/m³ and volume 0.5 m³ weighs 2400 × 0.5 = 1200 kg. Select "kg/m³" and "m³" in the calculator and it performs this density to weight conversion directly.

Use steel's density of about 7850 kg/m³ (490 lb/ft³) and multiply by the volume. One cubic meter of steel weighs 7850 kg (about 17,305 lb); one cubic foot weighs about 490 lb. Choose the "Steel (carbon)" preset in the calculator for instant steel weight calculations.

One cubic meter of pure water at 20 °C weighs about 998 kg (roughly 2200 lb), commonly rounded to 1000 kg (1 metric tonne). One US gallon of water weighs 3.785 kg, or about 8.34 lb.

Enter the density in g/cm³ and the volume in any unit, then set the result unit to "lb". Behind the scenes: 1 g/cm³ = 1000 kg/m³, and 1 kg = 2.20462 lb. Example: aluminum at 2.7 g/cm³ with a volume of 1 liter weighs 2.7 kg ≈ 5.95 lb.

Yes — this is one of the most common uses. Enter the liquid's density (e.g. diesel ≈ 850 kg/m³, milk ≈ 1030 kg/m³, honey ≈ 1420 kg/m³) and the volume in liters or gallons. Example: 200 liters of diesel weighs 850 × 0.2 = 170 kg.

About 150 lb. Standard concrete has a density of roughly 2400 kg/m³ (149.8 lb/ft³), so 1 ft³ × 149.8 lb/ft³ ≈ 149.8 lb. A cubic yard of concrete weighs about 4049 lb (1837 kg).

Density: kg/m³, g/cm³, kg/L, g/mL, g/L, t/m³, lb/ft³, lb/in³, oz/in³, lb per US gallon. Volume: m³, cm³, liters, mL, dm³, ft³, in³, yd³, US/UK gallons, quarts, pints, cups, fluid ounces. Results: kg, g, tonnes, lb, oz, stone, US and UK tons — plus newtons and pound-force.

The formula W = ρ × V is exact by definition. Real-world accuracy depends on your inputs: published material densities are typical values (steel ranges 7750–8050 kg/m³ depending on alloy), porous materials like sand vary with moisture and compaction, and measured volumes carry their own error. For critical engineering, weigh a sample or use a certified material data sheet.

Three usual causes: (1) the real material density differs from the textbook value — alloys, moisture content, and porosity shift it; (2) the volume was estimated rather than measured — hollow parts, rounded shapes, and packaging inflate it; (3) mixed units — e.g. entering g/cm³ while thinking in kg/m³ is a 1000× error. The calculator eliminates cause 3 by handling unit conversion itself.

Not quite. Density (ρ) is mass per volume (kg/m³); specific weight (γ) is weight-force per volume (N/m³), equal to ρ × g. Water's density is 1000 kg/m³ but its specific weight is 9810 N/m³ (9.81 kN/m³). This calculator works with density and reports both mass and force, so you can think in either quantity.

Compute mass = density × volume in kg, then multiply by 9.80665 m/s². Example: 2 m³ of steel = 15,700 kg → 15,700 × 9.80665 ≈ 153,964 N (≈ 34,613 lbf). The calculator displays this force equivalent automatically under every result.

Yes, completely free with no sign-up and no limits. It runs 100% in your browser — your numbers never leave your device — and works on phones, tablets, and desktops.

Yes, the math is identical: mass = density × volume works for gases too. Select the "Air" preset (1.225 kg/m³ at sea level) and enter the room or tank volume. Note that gas density changes with temperature and pressure, so use the density at your actual conditions for the best result.